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lib/exop/callback.ex
defmodule Exop.Callback do
@moduledoc """
Provides macros for callback handling.
## Example
defmodule CallbackModule do
use Exop.Callback
def process(operation, params, result, opts) do
# your callback handling code here
end
end
defmodule TestOperation do
use Exop.Operation
callback CallbackModule, return: true
parameter :a, type: :integer
parameter :b, type: :integer
def process(%{a: a, b: b}), do: a + b
end
By using `Exop.Callback` you need to implement `process/4` function which takes following params:
* operation module (`TestOperation` in the example above)
* params that were passed into the operation (`%{a: 1, b: 2}`)
* an successful result which was returned by the operation.
* opts is an open keyword list for metadata passing.
Callback operation has no effect on the result. but trigger a callback after success coming handy to send
PubSub prodcast or any side effect event without interrepting the main workflow.
"""
@type t :: __MODULE__
@doc """
Callback handling function.
Receives:
- operation module
- a map of parameters with which the operation was invoked
- an result tuple returned by the operation
- a keyword list defined as opts in within macro call.
"""
@callback process(atom(), map(), any(), keyword() | []) :: any()
defmacro __using__(_opts) do
quote do
@behaviour unquote(__MODULE__)
import unquote(__MODULE__)
end
end
end